Some dietary supplements labeled as containing “Bilberry Extract” are adulterated with lower-cost, non-bilberry ingredients that are not stated on the products’ labels, according to a new report in the nonprofit American Botanical Council’s fall 2012 issue of its peer-reviewed journal,HerbalGram.

Bilberry (Vaccinium myrtillus) fruit and its products can be found in health products, foods, and cosmetics, and are marketed as dietary supplements in the United States and as phytomedicines in the European Union. In 2011, bilberry dietary supplements were the 15^thbest-selling single-herb supplement in the mainstream market in the United States, which includes grocery stores, drug stores, and mass-market retail stores. Reported health benefits of bilberry are primarily in the vascular domain and include treatment of vascular insufficiency, capillary fragility, and retinopathy.

“Given global demand for this relatively high-cost, wild-harvested berry, bilberry supplies are reportedly rife with economic adulteration,” wroteHerbalGramarticle co-authors Steven Foster, an author and widely published botanical photographer, and Mark Blumenthal, ABC’s founder and executive director, and editor of HerbalGram.

According to the article, the world’s entire supply of commercial bilberry is wild-harvested, primarily in Scandinavian countries and in Eastern Europe. “[T]he relatively small region of growth for bilberries suggests that there is not much elasticity in the price of raw material,” the authors wrote. One industry expert quoted in the article explains that it takes 100 kg of hand-picked bilberry fruit to make 1 kg of extract, which can cost anywhere from $325 to $600 for the bilberry raw material alone, depending on seasonal supply and other factors. Therefore, considering other costs (e.g., refrigerated storage and transportation, extraction, etc.) the economics strongly suggest that some of the lower-cost bilberry extracts currently available in the global supply market are adulterated with other, cheaper, ingredients.

Some of the known adulterants include amaranth dye (also known as azo dye or Red Dye No. 2). [The dye is used to “trick” certain types of analytical methods, and is not to be confused with the food called amaranth (Amaranthus spp.).] Additionally, third-party laboratories have reported adulteration of commercial bilberry samples with charcoal, black soybean (Glycine max) hull and black rice (Oryza sativavar. indica) hulls. Other items include other lower-cost fruits containing anthocyanin pigments, the primary active compounds found in bilberry. Further, language confusion is a potential basis of adulteration; translation errors, including mistaking “blueberry” for “bilberry” or other similarly named species of the botanical genusVaccinium, can result in the use of improper material in some countries.

Industry awareness of bilberry adulteration has led to the development of advanced chemical analyses – including versions of high-performance liquid chromatography (HPLC) and other appropriate analytical methods – that can determine the precise contents of bilberry products. The active ingredients responsible for many of bilberry’s beneficial properties are known as anthocyanosides (or anthocyanins). According to the authors, “the mixture … in bilberry produces a unique pattern set that distinguishes bilberry from all other anthocyanoside sources.”

The article is the fourth installment in the ongoing ABC-AHP-NCNPR Botanical Adulterants Program, a collaboration of the American Botanical Council, the American Herbal Pharmacopoeia, and the National Center for Natural Products Research at the University of Mississippi. Previous articles produced by this program have detailed the history of adulterationof botanical ingredients (HerbalGram issue #92), the adulteration of skullcap(Scutellaria lateriflora) with germander (Teucrium canadense) (issue #93), and the adulteration of commercial “grapefruit seed extract”(supposedly derived fromCitrusx paradisi) with synthetic industrial disinfectants (issue #94).

The bilberry article was peer-reviewed for accuracy by numerous experts, including analytical chemists from independent third-party analytical laboratories.